Method of casting car-wheels.



J. K. GRIFFITH. METHOD OF GASTING GAR WHEELS. APPLIOATION FILED AUG. 8, 1912.

1 ,O66,604:. Patented July 8, 1913.

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Specification of Letters Patent.

Patented July 8,1913.

Application filed August 6, 1912. Serial No. 713,576.

To allwhom, it may concern:

Be it known that I, J'Aoon K. Gnntrrrn,

a resident of Pittston, Luzerne county, Pennsy Vania, have invented a new and useful Improvement in the Method of Casting CarlVheels, of which the following is a full, clear, and exact description, reference being had} to the accompanying drawings, forming part of this specification, in which- Figure 1 is a vertical section illustrating apparatus which may be employed in carrying out my improved method; and Fig. 2 is a similar view on a larger scale of a portion of the apparatus.

My invention has relation to' the manu facture of car wheels, and is more particularly an improvement over the method described and claimed in my Patent No.

. 790,202 of May 16th, 1905.

The object-0f the present invention is to provide a simple and e cient method where'- by not only all the advantages of the method of the said patent are retained, but which enables the manufacture of a composite ca r wheel in which thetreador tire portion of the wheel may be of a different characterof metal from the body of the wheel.

In accordance with my presentinvention,

the tread or tire portion of the wheel may be composed of either ahigh-carbon steel, or an alloyed steel, such as chrome steel, manganese steel, vanadium steel; tungsten steel,

etc., while the center portion is of ordinary low carbon steel. I

In the practice of my invention, I place a mold, such as shown at 2 in the accom anyingdrawings, and which is prefera ly a mold of the general construction shown and described in my said patent, upon a revolving table 3, and cause it to revolve at a sulficiently high rate of speed tocause the metal first poured into the mold to be driven by centrifugal force to form the rim or the tread portion of the wheel. This metal ma be poured into themold froma small auxi iary ladle 4: suitably placed above the mold, or suspended from alarge ladle 5, as may be desired. This auxiliary ladle is supplied with a sufiicient quantity of hard or alloyed steel to form the rim of the wheel, or to form so much of the wheel as it maybe desired to make hard. After this metal has been allowed to run into the mold, which is being revolved at a high rate of speed,

soft metal from the large ladle is allowed to pass into the same auxiliary ladle, and from .ter of the mold and mix urally come to the center of the tread are v eliminated.

The steel from which the mm is made can. 'be meltedeither 111'cruc1bles, or in a small furnace provided, for that purpose, or by any other approved method.

In order to cause the metal to pass more readily from the center of the mold, or h-ub portion, to the rim of the wheel when it is first poured, I preferably make the down wardly extending portion 6 of the hub as short as possible, while the top portion 7 is extendcd'to a considerable extent.

As before stated, I preferably use a mold of the general character shown and described in my said Patent No. 790,202, having a metallic rim portion of relativel large cross-section so as to afford a consid erable body of metal, sufiicient to produce relatively rapid cooling, the hubportion also being of metal, while the wcb-forming portions are of sand. This construction is of importance, since if a sand mold were employed throughout, and the metal intended to form the rim of the wheel was of less specific ravity than the metal used to form the cen er of the wheel, the fact that the two difi'erentmetals would be retained in fluid condition for a short time would cause the less dense metal to gravitate toward the cenwith the denser metal, or vice versa.

By my improved to make a wheel, the rim of which may be either of less or of greater density than the which are so nearly circular that it is not necessary to machine or grind them on the method, it is possible treadin order make their: perfectly round.

' This is. due tothe fact'tha't the inside of which are cast in light expanding chills mustalso be rounded up. My improved method overcomes this necessity. This is of especial advantage in the manufacture of wheels in, which the rim is of very hard -metal such aschrome steel, which i's very diflicult to grind. l In the method described in my said Patent 790,202, by causing a more rapid chilling; of themetal at the rim than in the web portion of the casting, -I was able to take adyantage of the fluid compression resulting from the contraction of the rim and exe'r-td inwardly in the plane of the web. By my present invention, I not only retain this advantage, but utilize the centrifugal force" of rotation to exert an outward compressive action upon the metal in the web. My present invention, therefore, enables me to form a wheel in which the rim portion of higher wear-resisting character, by its more rapid cooling maintains its identity during the casting operation, forming a'mo-re or less distinct annulus; while at the same time I ins e the proper filling out of the web portions of the casting and the densifying of the metal therei'mboth by the compressive forces exerted by the cooling rim, and also by the densifying centrifugal action.

-My invention also can be employed in the my hand. r

manufacture of wheels having a cast' ironv center and a steel tire,"the latter-being perfectly united to the body of: thewheel dur-" 40' ing the casting operation. In this manner I can make a wheel with a steel tire. of

a composition, such as chrome or manganese steel,- which is. so hardkthatit could not be .rolled into tire form. The present invenportions of the wheel, and innnediate1y thereafter pouring-into the mold molten metal of a diiferent compositionto form the hub and web portions of the-wheel, and causing the first named metal" to cool with comparative rapidity to form a substantially distinct annulus of the/wear-resisting metal, and cooling-the Web portion of the metal with much less rapidity, whereby it is subject for a longer period to the densifying action of the rotarymovement, and also to the compressive action of] the contraction of the said rim portion substantially as described. a

In testimony whereof, I'have hereunto set JACOB K. GRIFFITH. Witnesses:

JEMIMA CUTLER,

EARLEY M. JOHNSON. 

